The present invention concerns an arrangement for an indirect extrusion press for producing an extrusion product from a hot metal billet. More particularly, the present invention relates to an arrangement which finds particular utility in connection with an indirect extrusion press of the type described in applicant's copending U.S. application Ser. No. 836,629, filed on Mar. 5, 1986, the disclosure of which is incorporated herein by reference, wherein the press includes a plurality of containers arranged on a rotatable press turret. In such an arrangement the containers on the press turret are sequentially rotated through the extrusion axis of the press where extrusion actually takes place and through various working stations off of the extrusion axis where other functions are performed, such as removing an extrusion discard from a press container, cleaning a press container and loading a new billet into a press container.
The purpose of such a multiple container press is to maximize the efficiency of the press by minimizing the number of operations on the extrusion axis which are not involved in the actual extrusion of a billet. The foregoing application discloses a further time saving mechanization in connection with the changing of a container in the press turret. A relatively quick container changing procedure is desirable for overall press efficiency, for example when billets of different diameters are to be extruded, since the diameter of the cavity in the press container must match the diameter of the billet to be extruded, or when billets of a different metal are to be extruded, requiring a compatible replacement container.
The tooling of the press must also be changed to accommodate a billet of different diameter. It is a simple matter to load a die and pressure disc of appropriate diameter along with the billet into the press cavity. It is necessary, in addition, that the hollow pressing stem which pushes the die through the cavity of the container have an outer diameter corresponding to the diameter of the billet. Thus, in addition to changing the container to accommodate a billet of a different diameter than that previously extruded, it is also necessary to exchange the pressing stem with another pressing stem having the appropriate outer diameter. If the pressing stem is fixed to the ram, for example, by heavy duty bolts, this can be a time consuming process, resulting in significant downtime of the press. The present invention is therefore directed, in one aspect, to facilitating the changing of the pressing stem when it is desired to extrude a billet of a different diameter.
According to a further aspect of the invention, the configuration of the indirect extrusion press disclosed in copending application Ser. No. 06/836,629 makes it possible to utilize the main ram for the purpose of piercing the billets as well as pressing the billets to form an extrusion product. Although piercing the billets on the extrusion line does cut into the overall efficiency of the press in terms of decreasing the percentage of the press cycle time devoted to actual extrusion, the use of the main ram to pierce billets on the extrusion line according to this aspect of the invention, as will be described more fully below, offers an option which has the advantage of eliminating the requirement for a separate piercing machine, which is a costly piece of equipment. Additionally, by piercing the billets on the extrusion line, the billets do not require reheating as they would if pierced off of the extrusion line and subsequently transported to the press container for extrusion.